The superconductivity of Sr<sub>2</sub>RuO<sub>4</sub> under c-axis uniaxial stress.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35933412.
- Also identified by DOI 10.1038/s41467-022-32177-4 and PMC identifier 9357014.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Applying in-plane uniaxial pressure to strongly correlated low-dimensional systems has been shown to tune the electronic structure dramatically. For example, the unconventional superconductor Sr<sub>2</sub>RuO<sub>4</sub> can be tuned through a single Van Hove point, resulting in strong enhancement of both T<sub>c</sub> and H<sub>c2</sub>. Out-of-plane (c axis) uniaxial pressure is expected to tune the quasi-two-dimensional structure even more strongly, by pushing it towards two Van Hove points simultaneously. Here, we achieve a record uniaxial stress of 3.2 GPa along the c axis of Sr<sub>2</sub>RuO<sub>4</sub>. H<sub>c2</sub> increases, as expected for increasing density of states, but unexpectedly T<sub>c</sub> falls. As a first attempt to explain this result, we present three-dimensional calculations in the weak interaction limit. We find that within the weak-coupling framework there is no single order parameter that can account for the contrasting effects of in-plane versus c-axis uniaxial stress, which makes this new result a strong constraint on theories of the superconductivity of Sr<sub>2</sub>RuO<sub>4</sub>.